/****************************************************************************
 * Copyright 2009 Huascar A. Sanchez                                        *
 *                                                                          *
 * Licensed under the Apache License, Version 2.0 (the "License");          *
 * you may not use this file except in compliance with the License.         *
 * You may obtain a copy of the License at                                  *
 *                                                                          *
 *     http://www.apache.org/licenses/LICENSE-2.0                           *
 *                                                                          *
 * Unless required by applicable law or agreed to in writing, software      *
 * distributed under the License is distributed on an "AS IS" BASIS,        *
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
 * See the License for the specific language governing permissions and      *
 * limitations under the License.                                           *
 ****************************************************************************/
package com.gotobject.filter.ordering;

/**
 * @author huascar.sanchez@gmail.com (Huascar A. Sanchez)
 */
public abstract class AbstractOrdering <T> implements Ordering <T> {
    @Override
    public Ordering<T> thenBy(Ordering<? super T> operator) {
        return new ThenByOrdering<T>(this, operator);
    }

    /**
     * ThenBy Sorting object.
     */
    private static class ThenByOrdering <T> extends AbstractOrdering <T> {
        private final Ordering<T> first;
        private final Ordering<T> second;

        @SuppressWarnings({"unchecked"}) // todo: CCE is allowed here...
        ThenByOrdering(Ordering<? super T> first, Ordering<? super T> second){
            this.first  = (Ordering<T>) first;
            this.second = (Ordering<T>) second;
        }

        @Override
        public Iterable<T> of(Iterable<? super T> source) {
            return second.of(first.of(source));
        }

        @Override
        public String toString() {
            return "thenBy(" + second + ")";
        }
    }
}
